A joint military-police task force investigating a claimed civilian drone deployment to North Korea has interrogated a graduate student who claims to have flown the drone.

The task force said Monday that it summoned the student in his 30s, surnamed Oh, for questioning Saturday on suspicion of violating the Aviation Safety Act and the Protection of Military Bases and Installations Act.

Oh was questioned a day after investigators grilled a civilian, surnamed Jang, who co-founded a drone company with Oh. 

Friday marked the second time Jang was questioned. 

After co-founding the drone company, Oh and Jang had worked together as contract employees at the presidential office during the Yoon Suk Yeol administration and also had formed a youth organization related to unification. 

Oh earlier told a local media outlet that he flew the drones to verify the radiation level at the North’s uranium facility.

Meanwhile, the task force is also looking into allegations that Oh received support funds from the Korea Defense Intelligence Command.